We propose experiments to investigate preabsorptive satiety mechanisms in 3 syndromes of hyperphagia: the genetically obese (obob) mice, the ventromedial hypothalamic lesioned rats and in normal rats eating during the dark phase of the light-dark cycle. We also plan to study the effect of abdominal vagotomy and cholecystokinin (CCK-8) on food intake and body weight in genetically obese (obob) mice. Finally, we are investigating the deficits in thirst that occur after abdominal vagotomy.